Antibacterial resistance is a global clinical and public health problem that has emerged with alarming rapidity in recent years and, undoubtedly, will increase in the near future. According to the statistics of the Center for Disease Control and Prevention (CDC), infections with antibiotic-resistant bacteria cause more than 2 million illnesses and about 23,000 deaths each year in the United States. Recent research estimates that by 2050, 10 million people may die annually due to infections caused by antibiotic-resistant bacteria. Moreover, mortality due to infection is soon expected to be more than that caused by cancer. Antibiotic resistance will also have a cumulative cost of at least 100 trillion USD, more than one and a half times the annual world Gross Domestic Product (GDP) today. In the United States, there are about 47 million unnecessary antibiotic prescriptions issued each year. These unnecessary prescriptions are made to conditions that do not require antibiotics, such as viral infections which do not respond to antibiotics. Excessive use of antibiotics over the past few decades has led to the development of bacteria that is resistant to currently available antibiotics. Most newly developed antimicrobials are chemical variants of older agents; therefore, resistance can develop quickly. Indeed, bacterial strains resistant to many existing antibiotics are continually being isolated and there is an urgent need to identify new antimicrobial agents with improved activity against both Gram-positive and Gram-negative organisms.
Staphylococcus is one of most clinically important species of Gram-positive bacteria and methicillin-resistant Staphylococcus aureus (MRSA) causes many severe infections. The World Health Organization has included this bacterium in its list of the top 12 pathogens causing high morbidity and mortality worldwide. Due to the limited therapeutic options currently available to combat this bacterium, patients infected with MRSA are estimated to have 64% more mortality risk than patients infected with other non-resistant forms of the bacteria.